Optimization in multi-implant placement for immediate loading in edentulous arches using a modified surgical template and prototyping: A case report

Immediate loading of dental implants shortens the treatment time and makes it possible to give the patient an esthetic appearance throughout the treatment period. Placement of dental implants requires precise planning that accounts for anatomic limitations and restorative goals. Diagnosis can be made with the assistance of computerized tomographic scanning, but transfer of planning to the surgical field is limited. Recently, novel CAD/CAM techniques such as stereolithographic rapid prototyping have been developed to build surgical guides in an attempt to improve precision of implant placement. The aim of this case report was to show a modified surgical template used throughout implant placement as an alternative to a conventional surgical guide.

Bacterial leakage along the implant-abutment interface of premachined or cast components

In recent clinical studies, contamination of the inner parts of dental implants through bacterial penetration along the implant components has been observed. The aim of the present in-vitro study was to investigate leakage of Fusobacterium. nucleatum through the interface between implants and premachined or cast abutments. Both premachined (n = 10) and cast (n = 10) implant abutment assemblies were inoculated with 3.0 mu L of microbial inoculum. The assemblies were completely immersed in 5.0 mL of tryptic soy broth culture medium to observe leakage at the implant-abutment interface after 14 days of anaerobic incubation. Bacterial growth in the medium, indicative of microbial leakage, was found only in 1 out of 9 samples (11.1%) in each group. Both premachined and cast abutments connected to external hexagonal implants provide low percentages of bacterial leakage through the interface in in vitro unloaded conditions if the manufacturer`s instructions and casting procedures are properly followed.

Genetic relatedness of commensal strains of Candida albicans carried in the oral cavity of patients' dental prosthesis users in Brazil

The aim of this study is to describe the degree of yeast-colonization in diabetic and hemodialysed-users of dental prostheses. Individuals (306) were examined using an oral rinse technique in order to evaluate the incidence of yeast-carriage, and genotype of C. albicans. Yeasts were isolated from 68.4% (91/133) individual's dental prostheses users. Dental prostheses were found to be a significant factor for the yeast colonization (P < 0.05). Overall, the intensity of carriage was higher in diabetic patients as compared with health and hemodialysed individuals (P < 0.05). The isolation rates were: C. albicans (51.7%), C. parapsilosis (20.9%), C. tropicalis (14.3%), C. glabrata (6.6%), C. krusei (3.3%), C. rugosa (1.1%), and Pichia (Pichia ohmeri, 2.2%). Ready-To-Go RAPD Analysis Beads were used and primer OPJ 6 distinguished the C. albicans isolates found in prostheses users. All the isolates were grouped into 11 RAPD profiles in four main clusters and, the average S (AB) for the entire collection of 47 C. albicans isolates were 0.779 +/- 0.178. Over 85% of isolates had a similarity level higher than or equal to 0.8 reinforcing the idea that the use of dental prostheses, independently of the host's clinical condition, probably provides the necessary conditions for these strains to gain a growth-specific advantage over others.

Effect of abutment's height and framework alloy on the load distribution of mandibular cantilevered implant-supported prosthesis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Deformation of Implant Abutments After Framework Connection Using Strain Gauges

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Prosthetic Platforms in Implant Dentistry

The use of implant-supported prosthesis to replace missing teeth became a predictable treatment. Although high success rate has been reported, implant treatment is suitable to complications, failures, and limitations such as peri-implant bone loss after implant loading. Stress evaluation on the bone-abutment-implant interface has been carried out to develop new designs of prosthetic platform and to understand the stress distribution in this interface. Several types of prosthetic platforms are available such as external and internal hexagon, Morse cone connection, and the concept of platform switching. Therefore, this study aimed to critically describe the different options of prosthetic platforms in implant dentistry, by discussing their biomechanical concepts, clinical use, and advantages and disadvantages. It was observed that all types of prosthetic platforms provided high success rate of the implant treatment by following a strict criteria of indication and limitation. In conclusion, a reverse planning of implant treatment is strongly indicated to reduce implant overload, and the use of advanced surgical-prosthetic techniques is required to obtain a long-term success of oral rehabilitations.

Clinical Viability for Immediate Loading of Dental Implants: Part II-Treatment Alternatives

The treatment with implants aims to obtain a direct interface between bone and implant. The implant is kept load-free during 4 to 6 months in the 2-stage procedure, which is considered a requisite for osseointegration. However, this period is based on empirical principles and uncomfortable for patient. So, the immediate loading protocol was Suggested to submit implants to occlusal function after placement. This protocol has been applied for several conditions of edentulism. The aim of this study was to evaluate the treatment alternatives for immediate loading of complete and partial edentulous patients. In general, the studies have demonstrated high previsibility for rehabilitation of complete edentulous arches with full-arch, implant-supported prosthesis. The rehabilitation with immediate loading for maxillary overdenture is questionable because there is no longitudinal study in literature. The studies with partial edentulous arches have demonstrated high success rates for implants placed in the mandibular and maxillary anterior region. Additional care is recommended for posterior region mainly in the maxillary arch, and further studies are suggested to corroborate this treatment.

Resolution of a titanium implant fracture after a recurrent trauma

Post-traumatic complications occasionally lead to tooth loss as well as the need for future implants. However, rehabilitation with endosseous osseointegrated implants does not protect the patient from the risk of suffering a new trauma. Implant fracture and the damage of the hexagon are post-traumatic complications that guide the clinician to preparing a more intricate treatment plan. The authors present a clinical case of a recurrent trauma of maxillary implant fracture. The treatment plan was to remove the implants followed by autogenous bone grafting to correct the defect. Two titanium implants were replaced, followed by connective tissue graft after allowing complete the healing process of the bone graft to occur. In the postoperative period of 6 months, satisfactory results have been shown as regards soft and hard tissues wound healing.

Histometric Analysis of Bone Repair in Bone-Implant Interface Using a Polylactic/Polyglycolic Acid Copolymer Associated With Implants in Rabbit Tibia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Passivity Versus Unilateral Angular Misfit: Evaluation of Stress Distribution on Implant-Supported Single Crowns: Three-Dimensional Finite Element Analysis

The aim of this study was to evaluate the effect of unilateral angular misfit of 100 Km on stress distribution of implant-supported single crowns with ceramic veneering and gold framework by three-dimensional finite element analysis. Two three-dimensional models representing a maxillary section of premolar region were constructed: group 1 (control)-crown completely adapted to the implant and group 2-crown with unilateral angular misfit of 100 Km. A vertical force of 100 N was applied on 2 centric points of the crown. The von Mises stress was used as an analysis criterion. The stress values and distribution in the main maps (204.4 MPa for group 1 and 205.0 MPa for group 2) and in the other structures (aesthetic veneering, framework, retention screw, implant, and bone tissue) were similar for both groups. The highest stress values were observed between the first and second threads of the retention screw. Considering the bone tissue, the highest stress values were exhibited in the peri-implant cortical bone. The unilateral angular misfit of 100 Km did not influence the stress distribution on the implant-supported prosthesis under static loading.

Stress Analysis in Simulation Models With or Without Implant Threads Representation

Purpose: This study aimed to evaluate the influence of implants with or without threads representation on the outcome of a two-dimensional finite element (FE) analysis. Materials and Methods: Two-dimensional FE models that reproduced a frontal section of edentulous mandibular posterior bone were constructed using a standard crown/implant/screw system representation. To evaluate the effect of implant threads, two models were created: a model in which the implant threads were accurately simulated (precise model) and a model in which implants with a smooth surface (press-fit implant) were used (simplified model). An evaluation was performed on ANSYS software, in which a load of 133 N was applied at a 30-degree angulation and 2 mm off-axis from the long axis of the implant on the models, The Von Mises stresses were measured. Results: The precise model (1.45 MPa) showed higher maximum stress values than the simplified model (1.2 MPa). Whereas in the cortical bone, the stress values differed by about 36% (292.95 MPa for the precise model and 401.14 MPa for the simplified model), in trabecular bone (19.35 MPa and 20.35 MPa, respectively), the stress distribution and stress values were similar. Stress concentrations occurred around the implant neck and the implant apex. Conclusions: Considering implant and cortical bone analysis, remarkable differences in stress values were found between the models. Although the models showed different absolute stress values, the stress distribution was similar. INT J ORAL MAXILLOFAC IMPLANTS 2009;24:1040-1044

Comparison between complete denture and implant-retained overdenture: effect of different mucosa thickness and resiliency on stress distribution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of different mucosa thickness and resiliency on stress distribution of implant-retained overdentures-2D FEA

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of stress distribution between complete denture and implant-retained overdenture-2D FEA

The aim of this study was to compare the stress distribution induced by posterior functional loads on conventional complete dentures and implant-retained overdentures with different attachment systems using a two-dimentional Finite Element Analysis (FEA-2D). Three models representative of edentulous mandible were constructed on AutoCAD software; Group A (control), a model of edentulous mandible supporting a complete denture; Group B, a model of edentulous mandible supporting an overdenture over two splinted implants connected with the bar-clip system; Group C, a model of edentuluos mandible supporting an overdenture over two unsplinted impants with the O-ring system. Evaluation was conducted on Ansys software, with a vertical force of 100 N applied on the mandibular left first molar. When the stress was evaluated in supporting tissues, groups B (51.0 MPa) and C (52.6 MPa) demonstrated higher stress values than group A (10.1 MPa). Within the limits of this study, it may be conclued that the use of an attachment system increased stress values; furthermore, the use of splinted implants associated with the bar-clip attachment system favoured a lower stress distribution over the supporting tissue than the unsplinted implants with an O-ring abutment to retain the manibular overdenture.

Orbital Implants Insertion to Improve Ocular Prostheses Motility

The objectives of this study were, through a literature review, to point the differences between orbital implants and their advantages and disadvantages, to evaluate prosthesis motility after orbital implants are inserted, and to point the implant wrapping current risks. Sixty-seven articles were reviewed. Enucleation implants can be autoplastics or alloplastics and porous (including natural and synthetic hydroxyapatite [HA]) or nonporous (silicone). Hydroxyapatite is the most related in the literature, but it has disadvantages, too, that is, all orbital implants must be wrapped. Exposure of the porous orbital implant can be repaired using different materials, which include homologous tissue, as well as autogenous graft, xenograft, and synthetic material mesh. The most used materials are HA and porous polyethylene orbital implant. The HA implant is expensive and possibly subject corals to damage, different from porous polyethylene orbital implants. Porous implants show the best prosthesis motility and a minimum rate of implants extrusion. Implant wraps can facilitate smoother entry of the implant into the orbit and allow reattachment of extraocular muscles. They also serve as a barrier between the overlying soft tissue and the rough surface of the implant, protecting implants from exposure or erosion.